Commissioned in September 1944, she operated as a kaiten manned suicide attack torpedo carrier during World War II and was sunk in January 1945.

The Type C submarines were derived from the earlier KD6 sub-class of the Kaidai class with a heavier torpedo armament for long-range attacks.

[4] She was configured to carry four kaiten manned suicide attack torpedoes on her after deck, two of them with access tubes that allowed their pilots to enter them while she was submerged.

[4] When the plane tried to ascertain I-48′s nationality, she submerged, and the Mariner attacked her with two depth charges and a Mark 24 "Fido" acoustic homing torpedo.

[4] The hunter-killer group′s commander made the assumption that I-48 was damaged and would head for Japanese-held Yap at an average submerged speed of 3 knots (5.6 km/h; 3.5 mph).

[4] At 03:10 on 23 January 1945, I-48 was on the surface 15 nautical miles (28 km; 17 mi) northeast of Yap, proceeding southwest at 18 knots (33 km/h; 21 mph) when Corbesier detected her on radar at a range of 9,800 yards (9,000 m).

[4] Conklin observed huge air bubbles rising to the surface, soon followed by oil, wreckage, and large quantities of human remains.

[4] It marked the end of I-48, sunk with the loss of all 122 men aboard — her crew of 118 and four embarked kaiten pilots — at either 09°55′00″N 138°17′30″E / 9.91667°N 138.29167°E / 9.91667; 138.29167 (I-48) or 09°45′N 138°20′E / 9.750°N 138.333°E / 9.750; 138.333 (I-48), according to different sources.

[4] A motor whaleboat from Conklin later recovered pieces of planking, splintered wood, cork, interior woodwork with varnished surfaces, a sleeve of a knitted blue sweater containing human flesh, chopsticks, and a seaman's manual from the water 17 nautical miles (31 km; 20 mi) north of Yap.